1. Field of the Invention
The present invention relates a light control apparatus that controls incident light passing through an aperture.
2. Description of the Related Art
Various types of variable optical apparatuses have been conventionally used. Among them is an insertion type variable optical apparatus in which one or plurality of optical elements are moved into and out of the optical path by an electromagnetic drive source or other drive source to change the optical characteristics of the incident light passing through the optical path. The functions of this insertion type variable optical apparatus can be extended by providing a plurality of optical elements.
With improvements in the image quality of portable devices having an image pickup function and small-size optical apparatuses such as micro videoscopes in recent years, there are demands for improvements of the optical components such as lenses, stops and optical filters used therein. Specifically, there are increasing demands for replacement of conventional fixed focal length lenses, fixed aperture stops, and optical filters having fixed characteristics respectively with adjustable focus lenses, variable diaphragm apparatuses, and optical filters having variable characteristics. The above-described insertion type variable optical apparatus is focused on as an optical apparatus suitable for use in small-size optical apparatuses described above, because the insertion type variable optical apparatus can easily be made small for its simple structure. Japanese Patent Application Laid-Open No. 2006-330314 discloses such an insertion type variable optical apparatus that can easily be made small. The apparatus disclosed in this patent document comprises a plurality of light blocking members that control the quantity of light, a plurality of driving means for respectively driving the plurality of light blocking members by an electromagnetic driving force generated by a magnetic circuit, and a base member on which the light blocking members and the driving means are mounted. In this apparatus, a member that prevents the entrance of leakage flux is provided in between the drive means, whereby a reduction in the size of the apparatus and stable driving are achieved.
Nowadays, a reduction in the size of the apparatus is required. With a reduction in the size of the apparatus, a frictional force tends to be a detrimental factor that prevents stable operation of the apparatus, and the influences of the frictional force can be a dominant detrimental factor.
In the apparatus disclosed in Japanese Patent Application Laid-Open No. 2006-330314, the plurality of light blocking members are in contact with each other as they rotate. Therefore, the operation of one light blocking member may affect the operation of another light blocking member, which may lead to a malfunction of the apparatus.
The present invention has been made in view of the above situations and has an object to provide a light control apparatus having excellent operational performance.